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Flashcards

Antimicrobial Concepts

Katherine Havighorst VM607 Vet Med English 33 cards

Cards in this deck (33)

  1. 1What are the four quadrants of spectrum?Gram + Aerobic
    Gram - Aerobic
    Gram + Anaerobic
    Gram - Anaerobic
  2. 2What is the mechanism of action of bacteriostatic drugs?-inhibit protein synthesis or metabolism
    -prevents further cell division without killing the bacteria
    -normal host defense mechanism must participate
  3. 3How do bacteriostatic drugs react with other drugs?-can antagonize select bactericidal drugs
    -can become bactericidal if given in high doses or combined with select agents
  4. 4What is the mechanism of action of bactericidal drugs?kill the bacteria
    -cell wall synthesis inhibitors, DNA gyrase inhibition, DNA degradation during replication, membrane disruption
  5. 5Why can bactericidals cause superinfections?they are more likely to kill off normal flora than bacteristatics
  6. 6What is the process of a Kirby Bauer test?-add antibiotic impregnated discs to the surface of a bacterial agar plate
    -the drug diffuses on contact with agar
    -size of the zone of inhibition of growth predicts sensitivity
    -BUT. difficult to quality control
  7. 7Why might a 96-well Format Microtiter Plate be a better test than Kirby Bauer when determining sensitivity?-broth concentrations parallel serum concentrations, making it a better model than KB
    -uses dehydrated antimicrobials, which increases shelf-life
    -able to test a far greater number of drugs/drug concentrations
    -Quality control relatively easy, results are reliable
  8. 8Explain the use and process of an E-test-Enables testing of a single preferred drug for multiple organisms at a lower cost
    -Measure where the zone intersects the strip
    -Useful for fastidious organisms that grow poorly in broth
  9. 9What data is needed to establish a a breakpoint?Epidemiological: fit within the limits of clusters of susceptible and resistant bacterial populations
    Pharmacological: upper limit for susceptibility must be lower than levels that may be achieved in sera or tissues
    Clinical: the susceptible population should respond clinically and reasonably correlated to in vivo results
  10. 10What are reasons an organism may be intrinsically resistant to a drug?-they lack the target
    -they have an altered target
    -the drug cannot enter the organism
    -an efflux mechanism pumps the drug back out
    -an alternate metabolic route is used by the organism
  11. 11Why might an antimicrobial be placed into group D?-contraindication
    -residues
    -drug of last resort for humans
  12. 12List the 6 basics of antibiogram design1. Analyze and prepare an antibiogram AT LEAST anually
    2. include only final verified results
    3. include only species with data for 30+ isolates
    4. Include only diagnostic isolates (not surveillance isolates)
    5. Do not include duplicates from the same patient
    6. Report the % S for agents that are routinely tested and reported
  13. 13What is the value of MIC90 Tables?-Make more informed empirical tx decisions
    -Earlier tx to reduce losses
    -Represent a continuum; not a cutoff
    -You know you can have 90% likelihood of success treating with this antibiotic
  14. 14What 3 types of antimicrobial agents work by inhibiting cell wall synthesis?Penicillins
    Carbapenems
    Monobactams
  15. 15What are narrow spectrum penicillins?Penicilin G
    Penicillin V
  16. 16What are common aminopenicillins?Ampicillin
    Amoxicillin
  17. 17What are common penicillinase-resistant / antistaphylococcal penicillins?Nafcillin
    Methicillin
    Oxacillin
  18. 18What are common extended spectrum penicillins?Piperacillin
    Ticarcillin
  19. 19What are common B-lactamase inhibitors?Clavulanic ACid
    Sulbactam
    Tazobactam
  20. 20What is a common carbapenem?Imipenem
  21. 21What is a common monobactem?Aztreonam
  22. 22What is the MoA of penicillin?-Bind to transpeptidases [penicillin binding proteins] and inhibit peptidoglycan synthesis
    -inhibiting transpeptidases destabilizes cell wall
  23. 23Are B-lactams bacteriostatic or bactericidal?Bactericidal
  24. 24Why are B-lactamase inhibitors combined with penicillin?B-lactamase inhibitors extend the spectrum of penicillin to include bacteria that express B-lactamases
  25. 25What is the MoA of Carbapenems?Same as penicillin-bind to transpeptidases and inhibit cell wall synthesis
  26. 26When are monobactams used?-Only active against aerobic GNR
    -given in place of aminoglycoside for very narrow coverage of aerobic GNR like E. Coli
  27. 27Give common 1st and 3rd generation cephalosporinsFirst: cefazolin, cephalexin
    Third: ceftiofur, ceftazidime, cefovecin, ceftriaxone
  28. 28How do cephalosdporins compare to penicillins?Cephalosporins are
    -less sensitive to GI amidases
    -less sensitive to bacterial B-lactamases
    -less sensitive to alkalinity
    -resistant to acidity
  29. 29What drugs are inhibitors of ribosomal 30s subunit?Aminoglycosides
    Tetracycline
  30. 30What drugs are inhibitors of ribosomal 50S subunit?Macrolides
    Lincosamides
    Phenicols
  31. 31What are common macrolides?Group A: Tulathromycin, Tilmicosin
    Group B: Erythromycin
    Group C: Tylosin
  32. 32Are macrolides bacteriostatic or bactericidal?Bacteriostatic
  33. 33What are common types of Lincosamides?Lincomycin
    Clindamycin
    Pirlimycin

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Vet Med VM607 (Antimicrobials) Flashcards on Antimicrobial Concepts , created by Katherine Havighorst on 24/10/2019.
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